Currently, there are no effective treatments for disease recurrence following allogeneic hematopoietic stem- cell transplant (HSCT). T-cell therapy can target malignancies using mechanisms independent of chemo- radiotherapy, with non-overlapping and generally mild toxicities. Thus, we are investigating adoptive immunotherapy as a strategy to augment the graft-versus-tumor (GVT) effect after allogeneic HSCT. However, this approach has been limited by problems delineating immunogenic epitopes for a large number of HLA alleles, T-cell tolerance to leukemia-associated antigens, and the difficulty of manufacturing patient- specific T cells in a timely manner. As an alternative strategy, we propose to use T cells genetically modified to express a chimeric antigen receptor (CAR) specific a desired tumor antigen independent of MHC. To target B-cell malignancies, we have designed a CAR which re-directs the antigen-specificity of T cells to the B cell lineage-restricted cell-surface molecule CD19. CD19 is expressed on the majority of B-lineage leukemia or lymphoma cells, but is absent on hematopoietic stem cells and non-hematopoietic cells. Genetically modified CD19-specific T cells are activated via chimeric CD3-^ upon CAR binding CD19, resulting in antigen-dependent cytokine production, killing and proliferation. These preclinical data were used to open a Phase I clinical trial (BB-IND 11411) infusing autologous CD19-specific T cells (expressing the first-generation CAR) in patients with relapsed follicular lymphoma. In this grant, we propose a new clinical trial to infuse pre-prepared CD19-specific T cells derived from umbilical cord blood (UCB) in patients with relapsed B-lineage leukemia/lymphoma after allogeneic HSCT. Significantly, this trial will be (i) the "first-in- human" infusion of CD19-specific T cells after allogeneic HSCT, (ii) the first to infuse T cells expressing a second-generation CAR capable of providing a fully-competent T-cell activation signal (through chimeric CD3-[unreadable];and CD28), and (iii) the first to image distribution of genetically modified T cells and their activation status in vivo by positron emission tomography (PET), an example of radio-gene-therapy. We hypothesize that the a priori generation of banks of a homogenous population of UCB-derived HLA-unmatched CD19- specific T-cell clones will permit infusion of T cells in a safe and timely manner in a patient population with little chance of survival. T-cell isolation, genetic modification, and expansion will follow Standard Operating Procedures at MDACC, and T-cell doses will be manufactured in our Good Manufacturing Process (GMP) facility in accordance with quality control/assurance standards mandated by the FDA for a master cell bank. Lav language: T cells will be developed which can destroy B-lineage disease.